DIRECT POSITION PLUS VELOCITY FEEDBACK-CONTROL OF LARGE FLEXIBLE SPACE STRUCTURES

Feasibility of velocity control of large flexible structures with collocated sensors and actuators using velocity feedback was proved by Balas. Some previous extensions to position feedback and position control by Bar-Kana and more recently by Mufti were apparently limited by a condition relating the minimal natural damping ratio and the minimal natural mode frequency of the structures. This note shows that the previous sufficient conditions were overly restrictive and that position and velocity feedback can stabilize flexible structures with no need for internal damping.